1. Field of the Invention
The present invention relates to image pickup lenses and image pickup apparatuses, and more specifically to a technical field of an image pickup lens suitable for an image-pickup optical system included in an apparatus such as a digital still camera or a camera-equipped mobile phone having a solid-state image pickup device, and an image pickup apparatus including the image pickup lens.
2. Description of the Related Art
There are various image pickup apparatuses, including ones that are small in size and having solid-state image pickup devices, such as charge-coupled devices (CCDs) and complementary metal-oxide semiconductors (CMOSs). Examples of such image pickup apparatuses include a camera-equipped mobile phone and a digital still camera.
There has been an increasing demand for size reduction in such image pickup apparatuses. Accordingly, image pickup lenses to be included in these apparatuses are desired to be small with short total lengths.
Together with the size reduction of image pickup apparatuses such as a camera-equipped mobile phone, the numbers of pixels of their image pickup devices have also been increasing recently. Apparatuses including image pickup devices of megapixel or higher type are becoming mainstream. Accordingly, image pickup lenses to be included in such apparatuses are desired to have high lens performance so as to adapt themselves to the aforementioned image pickup devices having large numbers of pixels.
To provide a small, high-performance image pickup lens, three or more lens elements are desired to be included. Exemplary image pickup lenses each including three or more lens elements are disclosed in the following Japanese Unexamined Patent Application Publications: No. 2004-4566, No. 2002-365529, No. 2002-365530, No. 2002-365531, and No. 2006-293324.